Fusible plug



March 25 1924. 1,488,263

c. MANDRA FUS I BLE PLUG Filed Aug. 12. 1922 33 Char/es Mandm I N V EN TOR.

Mm. Wm

A TTORNEY.

, lar to the ordinary well Patented Mar. 25, 1924.

UNITED STATES CHARLES MANDKA, OF CORONA, NEW YORK.

FUSIBLE PLUG.

Application filed August 12, 1922.. Serial No. 581,411.

To all whom it may concern:

Be it known that I, CHARLES MANDRA, a subject of the King of Italy, and a resident of Corona, L. I., in the county of Queens and State of New York, have invented certain new and useful Improvements in Fusible Plugs, of which the following is a specification.

This invention provides a fuse plug of novel form which will indicate the line interrupted by the burning out of the fuse so that repairs may be quickly made and the line restored to normal or working condition without entailing the loss of time incident to looking u the line and obviating the ex ense atten ant upon such investigation to ocate and replace the burned out fuse.

The present invention, besides indicating the fuse burned out by the passage of an abnormal charge over the line, also admits of repairs being quickly made and economically, it being necessary to replace only the burned out fusible element which may be effected at a nominal cost and in a moments time.

For a full understandin of the invention and the merits thereof an also to acquire a knowledge of the details of construction and the means for effecting the result, reference is to be had to the following description and accompanying drawings, showing a preferred em odiment, and in which- Fig. 1 .is a cross sectional vertical view of a fuse plug in a closed or normal position;

Fig. 2 is a similar cross sectional view with the fusible element burned out and the lid of the plug in an open or indicative position;

Fig. 3 is a plan view of the fuse plug in the open position with the lid omitted to more clearly illustrate the inner parts;

Fig. 4 is a plan view of the fusible element fully developed.

Like characters of reference denote similar parts throughout the drawing and the following ecification.

The fuse in its general a pearance is siminown fuse plug and comprises a body of insulating material consisting of a shell 10 of substantially tubular sha e and a bottom piece 11, both externally t readed at 12, and held to other firmly by a similarly threaded meta shell 13 flanged over at 14 to press the bottom piece 11 against the end of shell 10. 15 is a metal rivet through the bottom piece 11 to which is fastened, preferably with solder, a metal arm 16 which is bent upwardly to form a standard 17 terminating in a hook 18. 19 is a cover lid of substantially annular shape, having a central opening 19 which is covered with a piece of mica 20. 21 is a fulcrum spring, one end of which is secured to body shell 10, and the other end to cover lid 19, in such a way that the lid will open with the spring 21 as its fulcrum, the spring having. the tendency to kee the lid in the open position indicated inig. 2.

22 is a metal lever lock trunnioned at 23 within inwardly projecting sockets 24 of metal shell 13. Look 22 consists substantially of 2 levers of which one. 25 is hook shaped to engage an aperture 26 at the inner wal of cover lid 19 when the same is in the normal position illustrated in Fig. 1. Another lever 27 of lock 22 is bent inwardly and is provided with a projection 28 on which is hooked a coil spring 29 of the retractile type which is anchored at its other end between body shell 10 and bottom piece 11. i

30 is a fusible element which consists pref erably of a fiat strip of metal of a low melting point. 31 is a narrowed central ortion of the element for the purpose of making the cross section of the element as small as possible and therefore more sensitive. .32 and 33 are holes for engaging, respectively, the end of lever 27 of lock 22 and the hook 18 of standard 17. While hole 32 is near the end of the fusible element, there. is a lon space 34 provided between the hole 33 an the other end of the element so that the same may be fingered with ease.

The operation of the invention is as follows:

When the fusible element 30 burns out by reason of an abnormal charge of current, the spring 29 pulls down the lever 27 of lock 22 which in turn withdraws lever 25 from aperture 26 in the cover lid 19 which is then forced open by action of fulcrum spring 21, thereby assuming the position shown in Fig. 2.

It is unnecessar to test the different lines to detect the location of the burned out fuse, inasmuch as inspection of the fuses from a distance will distinctly indicate which particular one is burnedout.

It is then a relatively easy and quick matter to insert a new fusible element in the plug by pushing over with ones finger the lever 25, so as to raise the end of lever 27 to ri g the same near enough to hook 18 to allow the insertion of a new fusible element, as explained above. The lid 19 is then pressed down to engage lever 25, which is efiected by slightly pushing it forward tothe lOGlZ, there being enough elasticity in i'nicruni 2i to do so.

VYlzile the cover lid has been illustrated to be equipped with a piece of mica, similar to the conventional form of plug to enable inspection of the fusible element, it is ob Vious that this is not necessary and that the may be made solid at the top.

It is understood that various changes in the "form, proportion and minor details of construction may be resorted to Without departing from the principle or sacrificing any of the advantages of the invention as defined in the appended claims.

lVhat I claim as new, is:

In a fusible plug, the combination of a body, a lid, a lock and a fusible element, and means to open automatically the lid when the said fusible element is burned out.

2. In a fuse plug consisting of a body and a lid, the combination within the plug of a loclr, a fusible element and means to release the lock; and means to open the lid.

3. In a fuse consisting of a body and a lid, a lock securing the lid to the body, a standard within the body, a fusible element connecting the lock with the standard, means to normally keep the loci: in an open posimasses tion, and means to normally keep the lid in an open position.

l. In a fuse lug consisting of a body and a lid, the com ination within the fuse of a lock securing the lid to the body, a fusible element and a standard, and. means to open the lock and release the lid when the said fusible element is burned out.

5. In a fuse comprisin a body and a lid, the combination w1thin tie fuse, of a look, a fusible element, a standard, and means adapted to open the look when the fusible element is burned out.

6. In a fuse plug consisting of a body and a lid, the combination within the fuse of a lock securing the lid to the body, a fusible element, and means to open the lock and release the lid when the said fusible element is burned out,

7 A fuse comprising in combination a body, a lid, a standard, a lock securing the lid to the body, a fusible element connecting the said standard and lock, means to release the lid and means to keep the lid in an open position when the said fusible element is burned out.

In testimony whereof I have hereunto set my hand and seal in presence of two subscribing witnesses.

CHARLES MANDRA. 1,. 8.] 

